Rock drill



R. H. SMICKLE Aug. 30, 1932.

ROCK DRILL Filed May 19, i928 2 Sheets-Sheet l HIS ATTORNEY 2 Sheets-Sheet 2 Mr., N@

INVENTogz.

m ndl'mwlrle BYZ @c HIS ATTORNEY ,Ray

DHH D Patented Aug. 30, 1932 WCE ' 5 RAYMOND ni. sM-rcKLE, or BELVIDERE, NEW JERSEY, AssrGNon To rNeaasoLnn-AND COMPANY, or JERSEY CITY, NEW JERSEY, a; coRroRATi'oN or Naw JERSEY nocK DRILL Application iled May 19, 1928.V Serial N0. 279,027,

expedite the drilling operation, and to reduce vibration and shock incident tok drilling to a minimum. 5

Other objectsV will be in part obvious and in part pointed out hereinafter.

In the drawings accompanying the specifiecation and in which similar reference characters refer tosimilar parts,

Figure 1 is a longitudinal sectional elevation, shown diagrammatically, of a rock drill having a plurality of pistons and showing the pistons in one of their limiting positions,

Figure 2 is a similar view showing the pistons in the other extreme positions, andV Figure 3 is a longitudinal diagrammatic sectional elevation of a rock drill showing a modification of the invention; f l

Referring to the drawings, and at first more particularly to Figures 1 and 2, A designates a cylinder', B a front head and C a back head of a rock drill. The cylinder. A, the front head B and the back head C in this in stance comprise the casing` parts which may 30 be held in assembled relationship in any suitable manner as for instanceby the usual side bolts (not shown).

` In accordance with the practice of the in-` vention, the cylinder A has a bore D compris- 7335 inv in this instance aV forward reduced porticn E and a rearward enlarged portion F.

In the enlarged bore F and adjacent the reduced portion E of the bore D is a wall or plate Gr which divides the bore into forward and rearward piston vchambers H and J respectively. The plate G may bemaintained securely in position by means of a sleeve K disposed in the enlarged portion F of the bore D to bearV withv one end against the plate and with its other end against the back head C.

The sleeve K may be firmly clamped between j" the plate G and the back'head C or may be secured in position-'in any suitable manner..

Disposed within the pistonv chamber Jwis a 5G- piston L having a head O slidably guided by the sleeve K and a reduced forward extension or stem l? which extends slidably through an aperture Q in the plate G 'and into the pistonchamber Htc deliver blows of impact l 'to anfanvil blockR at the front end of the cylinder. In this. instance the anvil block R is disposedin a. cavity VS in the rearward end of the front head B to transmit the blows of the piston L to -a working implement T which extends slidably into the front head. i

. The piston chamber H is likewise provided with a piston. `This piston designated by U" comprisesa head V which lies in the piston chamber H and an extensionlvlT which in this instance extendsy slidably into a bore X in the vfront end of the cylinder to deliver blows against a head Y of the anvil block R. The piston U has a bore Z which acts as a guidingV surface for the stem P' of the piston L. The front end ofthebore Z in this instance also'acts as a. guiding surface for a stem b of the anvil bloclr` R and against which the extension Pof the piston L may strike;

'llhe'leirgth ofthe stem of the anvil block is determined by the particular type of piston used in the rearward piston chamber J. If a piston without an extension is used, the stem b may of course be of a length to'eX- tend into the piston chamber J. Conversely, the extension P of the piston L may be of such length that it may strike directly against the anvilV block R, thus omitting the stem b. 'The piston chambers H and J are provided withexhaust ports c andd respectively which may lead directly to the atmosphere and are controlled in thisl instance by theA pistons within the respective piston chambersi For the sake of simplicity of illustration, the drill is shown provided with suitable valve mechanism, as distinguished from integral portions of one or both of the pistons for controlling the admission of pressure fluid into the piston chambers to actuate the pistons, The drill is accordingly provided with a valve chest e having a valve chamber in'which is disposed a distributing valve 'g of the spool .type. v The valve `g has forward rearward end heads hand respectively and an enlarged central flange 7e adapted to cooperate with inner end surfaces 0 and p asV of bushings g and r respectively in the valve pressure fluid supplied to the drill through an opening s adjacent the innermost ends of the bushings g and r. Ports t and a in the valve chest e are controlled by the end heads and j respectively.

inasmuch that the particular valve structure forms no part -of the present invention and is shown merely as one type of means for effecting the distribution of pressure iiuid to the piston chambers, a detailed description thereof is considered unnecessary. Reference is therefore made to only so much of the valve structure as may be helpful in obtaining a clear understanding of the invention and its operation.' Y v Leading from the valve chamber f at a point intermediate the opening s and theport u is an inlet passage 'u which opens atits otherk end into a passage w in the cylinder A. The passage w has rearward and forwardA f ports zu and y which openinto the corresponding ends'fof the piston Chambers J and H.

In the construction shown the admission of lpressure fluid to the contiguous ends of the piston chambers H andV J is effectedv in this instance through a passage a opening into.

the valve chamber 7" at a point intermediate the opening s and the port z5.V The passage e has branches 2 and 3 which open into the rearward and forward ends of the piston chambers H and J respectively.

In drills embodying the present invention and in which the distribution of pressure fluid is controlled by a valve, such as that shown in the drawings, the action or movement of the valve is preferably controlled by the pistons or, as'illustrated, by one of the pistons. The `cylinder is accordinglyprovided with crossed kicker passages 4 and 5'.` The kicker passage 5 opens into the cylinder rearwardly of the lexhaust port d and at its other end opens into the forward end of the valve chamberf. The kicker passa-ge 4 opens with one end into the cylinder at a point'forwardly of the exhaust port 0l and communicates at its other end with the rearward end of the valve chamber f.

The operation of the device so far dedescribed is as follows: With the valve g in the forward limiting position and the pistons Land U in the rearward and forward ends respectively of the piston chambers J yand H, pressure fluid entering the valve chamber ,f rearwardly of the flange will flow through.

the passages o and fw into the rearward end of the piston chamber J and into the front end of the piston chamber H.

The introduction of pressure fluid Vinto these ends of the piston chambers will cause the piston U to be impelled in a rearwardly the piston U will have reached a position 1 with respect to the plate G substantially the 'same as the piston L.` This is a preferred arrangement since the jars or vibrations resulting from the impact of. the piston L against 'the anvil block will belnullified' by the force of the piston U against the cushion of air compressed in the rearward end of the piston chamber H. However, not all of the air entrapped inthe contiguous ends of the piston chambers H and `J during these movements-of the pistonswill be compressed, as during a portion of the strokes of the pistons the air entrapped in the piston chambers will be expelledthrough the passages 2, 3 and a. into the valve chamber f and thence through the port to the atmosphere.

During this movement ofthe pistons, the kicker passage 5will be uncovered and pressure fluid'from the rearward end of the piston chamber J i will thence flow through the passage 5 intothe front end of the valve chamber f andact against the lfront end of the .head 7L to throw the valve g rearwardly to the position illustrated inFigure Q.

Shortly after the passage 5 has been uncovered, the pistons Land U lwill `uncover the exhaust ports d and c to permit the escape of pressure iiuid from the piston chambers tothe atmosphere. c

Upon reversal of the valve g, the' port t will be covered-'by the head /L of the valve and the port a will be uncovered by the head j. In this position of the valve pressure fluid will ilowfrom the opening s into the valve chamber @thence through the passages a, 2 and .Sinto the rearward and front ends of the piston chambers H and J respectively. The pressure fluid thus admitted will retractV the piston L to its initial position and will impel the piston forwardly to deliver its blow Vagainst the anvil block.

While the pistons are moving in the directions described, the kicker passage 4 will be uncovered by the piston L and pressure fluid will thence pass through the kicker passage 4 into the rearward end of the valve chamber vfto again throw the valve forwardly. As the piston L continues in the rearwardly7 direction and the piston U' in the forwardly direction, the exhaust ports d and c will be uncovered by the pistons to permit the escape of pressure fluid from the pistonchambers to the atmosphere. e r, Y Y

The air compressed in the piston chambers in the ends towards which the pistons areV traveling will be expelled through the passages fw and o into the valve chamber f from whence it will` escape to the atmosphere through the passage M For the sake of symmetry and',simplicity` of illustration, the pistons are arranged coaxially with respect to each other and only two pistons are employed. It will, however, be readily apparent to those skilled in the art that the principle disclosed in the drawings is susceptible of further modification, depending` upon the amount of drilling which it is desired to obtain within a given timev and other considerations, such as weight and proportions which the work for which the drill is intended will permit.

The advantages of the present invention will be readily apparent to those skilled in the art. Foremost of these advantages are the elimination of vibration which will greatly prolong the life of the drill; the increased number of blows in a given period of time which may be obtained by the use of a plurality of pistons and, the consequent greater footage of drilling than may be obtained by means of drills of the type heretofore employed. These advantageous results may be obtained without constructing the pistons of such proportions and weight as to be detrimental to the elements against Which they strike or react.

The modified form of the present invention illustrated in vFigure 8 differs from that shown in Figures l and 2 in that only a single piston chamber 6 is employed. This piston chamber 6 may, as illustrated, be of uniform diameterthroughoutitslength,andthepistons L and U may be guided directly by the said piston chamber. Due to the fact that only a single piston chamber is employed, the inlet passage a is provided with only one branch 7 which opens into the cylinder at a point intermediate the exhaust ports d and e for driving the piston U forwardly and the piston L in a rearwardly direction. The admission of pressure fluid to the ends of the piston chamber is effected through the passages v and (w as in the modiication previously described. There is no partition or wall used between the pistons in this instance. The pistons are prevented from striking each other by the air I claim:

1. A rock drill comprising a cylinder having atmospheric exhaust ports spaced relatively to each other, means in the cylinder between the exhaust ports dividing said cylinder into a plurality of coaxial piston chambers, a piston in each chamber controlling the exhaust ports, means for controlling the distribution of pressure `iuid to the cham-k .and a reduced portion forming a piston chamber, a sleeve in the enlarged portion to form a second piston chamber, a head between the chambers, hammer pistons in the piston chambers, and means for introducing kpressure uid into the pistonvcharnbers to cause said pistons to move simultaneously in opposite directions.

In testimony whereof I have signed this speciiication.

RAYMOND I-I. SMICKLE.

compressed by the pistons as they approach each other.

The operation of this modified form of the invention is in all essentialrespects like that illustrated in Figures l and 2 with the exception, however, that the pressure fluid for driving the piston U forwardly and the pist0n L rearwardly is admitted directly between the pistons and a portion of the compression formed by the pistons as they approach each other is exhausted through the passages 7 and a into the valve chamber.

The kicker passages 4 and 5 are also controlled by the head O of the piston-L and the inletl passages are also preferably so arranged that the pistons will simultaneously hereinbefore set forth. 

